Quercetin Supplements Guide

What is Quercetin?

Quercetin is a flavonoid, a pigment that imparts colors to flowers, fruits and vegetables. Flavonoids are antioxidants, compounds that neutralize free radicals and protect your body against free radical-related damage.

Quercetin is as an added ingredient in pre-packaged foods, beverages and sports supplements. It may be manufactured as a standalone supplement or paired with the digestive enzyme/antioxidant bromelain, with vitamin C or with other nutrients.

Quercetin is so common and abundant in the foods you eat, your average daily consumption might already fall between roughly 5 to 40 milligrams, according to WebMD. If you consume lots of fruits and vegetables, your average daily consumption might be upwards of 500 milligrams.

Ten common natural dietary sources of quercetin include:

Black and green tea

Red kidney beans

Broccoli

Red Delicious apples

Red onions

Kale

Fennel

Blueberries

Olive oil

Red Wine

Quercetin also occurs naturally in certain kinds of honey from various plants and is 79 percent more abundant in organically grown tomatoes than conventionally grown tomatoes. Quercetin exists in fat-soluble and water-soluble forms. Quercetin-chalcone and dihydroquercetin are examples of the latter.

Both forms share the same qualities and health benefits, although research confirms that fat-soluble quercetin specifically protects red blood cells against oxidative damage.

Benefits of Quercetin

As mentioned above, quercetin is an antioxidant. Antioxidants are substances that scavenge free radicals throughout your body. Free radicals are natural byproducts of metabolism, exercise, stress, the effects of poor diet and pollution.

Free radicals are atoms possessing unpaired electrons. Antioxidants are the only substances in nature that can donate electrons without themselves becoming free radicals. Long term free radical damage is a primary, underlying cause of disease, malignancy, everyday sickness and premature aging.

Precautions

Quercetin is generally safe for healthy adults. However, there are side effects related to high daily intake. Common daily oral dosages are roughly 1,000 milligrams or less broken up into at least two doses.

There are no established optimal dosages. Product purity and potency varies between brands, making it more difficult to accurately gauge safe dosages on a case-by-case basis.

Long term side effects of usage at 1,000 milligrams twice daily are unknown. Dosing intravenously seems to carry greater risk. Some known side effects are:

Upset stomach

Tingling in the arms and legs

Headache

Kidney damage

Doctors do not advise pregnant women to take quercetin. Increased appetite and food consumption paired with quercetin supplementation among pregnant women might lead to dangerously high exposure and subsequent toxicity.

Quercetin inhibits an important liver enzyme, CYP3A4. CYP3A4 factors directly into the metabolism of prescription antibiotics and drugs, such as cyclosporine.

Inhibited CYP3A4 and impaired liver function may lower the critical amounts of these drugs in your blood or change their effects entirely. With other substances, such as digoxin and fluoroguinolones, quercetin seems to either increase each drug’s inherent risks or reduce their efficacy, as noted above.

Quercetin causes corticosteroids to remain in your body longer than usual. Exposure to corticosteroids for any period increases the possibility of certain side effects:

High blood pressure

Fluid retention

Weight gain

Thinning bones and fracture

Except for quercetin’s negative interactions with certain prescription drugs, all of these side effects pertain to high dosages of quercetin taken over extended periods. There are little to no side effects when you take quecetin appropriately and in safe dosages.

Always speak with a medical professional or doctor before taking any supplements. Always read the product label for instructions and directions.

Taking Quercetin

Oral ingestion is the safest and most common way to administer quercetin. Pill and capsule are widely available forms, usually stacked with another vitamin, antioxidant or flavonoid.

Recall that there are bulk powdered versions of quercetin available as well. You can transfer powder to capsule sizes of your choice or mix it with smoothies, workout drinks and nutritional beverages.

If you’re struggling with hay fever, other seasonal allergies or reactions to cat dander, shoot for about 800 milligrams daily. Divide the dose into two equal amounts between meals.

What to Look For in a Good Quercetin Product

There are no standardized formulations of quercetin even from top manufacturers, so product bench markers do not exist that definitively reference value and purity. Instead, appraise the manufacturer of a particular quercetin product to deduce the product’s quality.

Here are some encouraging qualities to look for in a supplement manufacturer:

Positive reputation among customers

Majority of customer reviews are favorable

Awards, citations and recommendations from trusted professionals, the media and industry authorities

GMP certification

USP verification

Public endorsements from fitness professionals unaffiliated with the manufacturer

Checking off one of more of the above items provides you with concrete criteria with which to evaluate a prospective supplement. When in doubt, ask around. Talk to your doctor.

Commence your supplement regimen with low doses to assess tolerance. Try several reputable manufacturers to gauge supplement efficacy. Discontinue use of a particular brand if it does nothing or makes you sick.

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